SE-B-462,638 discloses a means for fixing an elongate prosthesis, such as the stem of a femural prosthesis, to living tissue which defines a cavity in which a length of the prosthesis is received with a gap to the boundary of the cavity. Essentially the entire gap is filled with loose, but packed grains of a biocompatible material, said grains interlocking. As an example of granular material titanium is mentioned, and the grains are stated to be irregular, essentially non-elastic and preferably porous, the latter property being said to bind growth of bone tissue which has grown from the osseous wall. The porosity has been obtained by blowing gas through a melt of the granular material.
U.S. Pat. No. 5,217,496 discloses an implant suited for use in living bone tissue and comprising a support of titanium having a porous outer surface and an attached layer of a mixture consisting of disintegrated living bone tissue and titanium powder. The mixture is supplied with nutriment which makes the disintegrated bone tissue grow and form tissue which connects the disintegrated bone tissue and the titanium powder with each other and with the support.
U.S. Pat. No. 5,676,700 discloses biocompatible structure elements for repair, reinforcement and replacement of bone tissue, said elements being indicated to form an osteoconductive or osteoinductive matrix in a bone tissue cavity. The material of the elements can be titanium and the elements are said advantageously to be microporous for ingrowth of natural bone.
In the above documents, porosity of biocompatible materials is thus pointed out to cause something favorable for binding of bone tissue.